Generally, it is sometimes desired to determine the location and the orientation of a particular region inside an object from outside the object. For a specific medical example, there is an injection in a mental foramen in the operation of oral surgery. The mental foramen is a hole of a few millimeters in a skull through which nerves pass. In some treatment, the necessity occurs that a drug is injected into a mental foramen by injection. For that injection, it is necessary to specify the location and the orientation of the mental foramen through the surface of an object (the skin surface in this case). However, in typical X-ray photography (x-ray radiography), only the relative two-dimensional shape of the internal tissue can be known.
For an apparatus which allows three-dimensional measurement of the particular region inside an object including a body, there is a CT apparatus. However, the CT apparatus is a very expensive apparatus, and in the use case considered here as an example, there are problems of large effort required for measurement and a great X-ray radiation exposure to a patient.
On the other hand, JP-A-S58-65142 discloses an imaging diagnostic apparatus in which an X-ray imaging apparatus is provided that takes a front image and a side image with X-rays, the two images are shown on a display, the region of interest is indicated by a light pen to show an elliptic front image and a rotating elliptic side image of the region of interest, and the rough shape and the location of the region of interest are known three-dimensionally.
In addition, JP-A-H03-10151 discloses an object inspection apparatus in which, X-rays are applied from different directions while a target object for inspection is being moved at a predetermined rate, and a failure area in a target object for measurement is inspected three-dimensionally based on image signals of X-rays having passed through the target object for inspection.
In addition, JP-A-H07-92111 discloses a defect test apparatus in which a target object for inspection is fixed, an X-ray source is moved to allow X-rays to transmit from two places, and the depth of a defect part of the target object for inspection is detected using the difference between the amounts of X-ray transmission.
Moreover, JP-A-H09-187448 discloses an X-ray imaging diagnostic apparatus in which X-ray images are taken from a plurality of directions, quantitative analysis is performed for a diagnosed area such as a blood vessel and a heart of a target object based on the X-ray images, and the diagnosed area is known three-dimensionally in consideration of error caused by fluctuations in the depth orientation.